A double-blind study is a study in which both the person implementing the experiment and the participant(s) are not aware of which individual is receiving the experimental treatment. The purpose of a double-blind experiment is to ensure that the results are not biased. This approach is frequently used in the research field by not only scientists and psychologists but also in the legal process. The benefits of this type of study is the increase in reliability and validity of the experiment.

Medication Experiments

A double-blind experiment is beneficial when testing a specific medication. Half of the participants are given the medication, and the remaining participants are given a placebo. A placebo is an inactive substance such as a sugar pill that looks identical to the medication. By utilizing a placebo, the study remains free from being altered as neither the participants nor the researcher knows who is receiving the medication. This provides valid and reliable results.

Taste Testing

We have all seen the commercials where the individual is asked to determine which beverage tastes better. Even given the best controls on the experiment, the experimenter might push one soda closer to the participant, or make sure that one drink is colder than the other. By completing these types of moves, the participant may be skewed which can cause invalid results. Using the double-blind approach, none of the individuals involved in the study are told which cup contains the targeted soda.

Computer Generated Survey

A survey is another method utilized by researchers when preforming experiments. Computer-generated surveys are double-blind experiments as the participant is completing the survey online and unaware of the researcher's targeted hypothesis. The researcher is not aware of who is participating in the experiment. In this scenario, since the participant is unknown, the study is free from interviewer bias.

Forensic Application

In police work, the officer will show a set of photos to the witness and ask that the witness identify the suspect. This is referred to as a single-blind test. The issue with this approach is the officer may have subtly influenced the witness' identification. Some law enforcement agencies are implementing a double-blind procedure to ensure identification accuracy. In this approach, both the officer and the witness do not know who the suspect is during the identification process.

About the Author

Susan Henrichon has more than 25 years of experience in education. She has taught special education and possesses administrative experience in the public school setting. She holds a Master of Education in special education from Westfield State University and a Certificate of Advanced Graduate Study in educational administration from the University of Massachusetts.